Sound reproducing or recording needle



Jan. 7, 1936. L. E. TURNER 2,026,760 I I SOUND REPRODUCING or: RECORDINGNEEDLE Filed March 11, 1935 Patented Jan. 7, 1936 NEE DLE

Louis E. Turner, Chicago, Ill. Application March 11, 1935, Serial No.10,372

4 Claims.

l longed use; which is provided with a very hard wear-resistingrecord-engaging portion which will retain its correct shape andusefulness in sound reproduction or recording much longer than needleswith the alloys heretofore used; 15 which is providedwith arecord-engaging portion formed of an alloy-metal having no grain and ofexceptional hardness and which is adapted to receive a very smoothfinish and shape to insure a smooth line contact with sound-creatin 20undulations forming theside walls of a groove in a record, to achieveperfect sound reproduc tion or recording of sound and to minimizescratching and record noises; and other objects which will appear fromthe detailed description 25 of the invention.

These objects are attained primarily by forming the record-engagingportion of a metallic needle of a hard wear-resisting alloy known astitanium carbide. This alloy practically elimi- 30 nates wear so as tomaintain at substantially constant value the volume and quality of soundreproduced or recorded during prolonged use of the needle. It is notsusceptible to rust nor corrosion and is efiicient in effecting fulltone re- 35 production or recording. It has no grain and is adapted toreceive a very fine smooth finish and to be properly shaped to insure asmooth line contact with the side walls of the groove in a record tominimize scratching and insures sub- 40 stantially perfect reproductionor recording of sound.

The invention consists in the several novel features hereinafter setforth and more particularly described by claims at the conclusion. 5 Inthe drawing, the figure is a perspective of a needle embodying theinvention.

In the exemplification of the invention illustrated in the drawing, theneedle comprises a round body portion or a shank a usually formed 5 ofsteel, phosphorousbronze, Monel metal, or other suitable metal and arecord-engaging portion or tip b fused or otherwise suitably secured tothe metal forming the shank. The record-engaging portion b is formed ofan alloy-metal known as 55 (titanium carbide. The tip or record-engagingportion may be of any suitable shape known in the art. In manufacturingthe needle, the record-engaging portion b is fused to the shank a and,if desired, swaged into the desired shape to form the record-engagingportion of the needle. The tip portion b is then ground and shaped to 5fit the grooves in the record so that no appreciable weight is carriedby the undulations forming the side walls of the groove. This is done byslightly rounding the lower end of the needle so the weight of theneedle and sound box will be centered upon the smooth bottom of thegroove 'to minimize the usual record noises, such for example, as areproduced by surface scratching.

When the record-engaging portion is made of titanium carbide, which hasno grain and is of extremely fine texture, substantially no wear will presult from a line contact with the sound-creating undulations andconsequently the usual record noises are eliminated. This alloyeliminates wear from friction between the needle and the undulationsbecause the alloy has no grain and is of extremely fine texture. Thisresults in keeping' the needle serviceable for eflicient sound recordingor reproduction longer than known types of bi-metallic needles whichhave been formed of coarse grained or porous metal alloys of lesserhardness than titanium carbide. The titanium carbide record-engagingportion has a hardness of approximately 9.3 and is practicallyindestructible, and by reason of its extremely fine non-porous texturehaving no grain, the point can be highly polished to. eliminate wear andscratching. The record-engaging portion retains its proper shaperelatively to the groove, so that it does not scratch or unduly wear therecord.

The invention is not to be understood as restricted to the detailsdescribed and may be used in connection with a shank portion of anysuitable metal or metal-alloy and may be used in a record-engagingportion of any suitable known shape.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent is:

1. A phonograph stylus comprising a record- I engaging portioncontaining titanium carbide.

2. A phonograph stylus comprising a shank of suitable metal and arecord-engaging portion containing titanium carbide.

3. A phonograph stylus comprising a body of suitable metal anda metaltip composed of titanium carbide.

4. A phonograph stylus comprising a body of suitable metal and a metaltip composed of titanium carbide fused on the shank.

LOUIS E. TURNER.

